The answer is a pedigree chart.
Pedigree charts are used to explain the occurrence of particular genes from one generation to the next. It gives enough information about family disease history. They are used in families to find out the probability of inheriting some disease. So, if Maria and Juanita are cousins and the genotypes of other members of their family are known, the pedigree chart could predict their genotypes. Still, it is not as precisely as DNA test.
